摘要:
J . C'HF_M. soc. DALTON TRANS. 1995 2317 Copper( 11) C h lo ride4 - Methyl benzot riazole Chemistry: Variation of Product as a Function of Metal-to-Ligand Reaction Ratio; Synthesis, Structure and Properties of a Dinuclear Complex and a Novel Chain Polymer with Two Alter na t i ng C h ro mo p ho res Konstantina Skorda,a Evangelos G. Bakalbassis,*Sb Jerzy Mrozinski,c Spyros P. Perlepes,*na Catherine P. Raptopoulou and Aris Terzis * s d a Department of Chemistry, University of Patras, 265 00 Patras, Greece Aristotle University of Thessaloniki, 540 06 Thessaloniki, Greece Laboratory of Applied Quantum Chemistry, Department of General and Inorganic Chemistry, Institute of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 503 83 Wroclaw, Poland Institute of Materials Science, NRCPS 'Demokritos: 753 70 Aghia Paraskevi Attikis, Greece The 1 : 2 and 1 : I reactions of CuCI, with 1 -methylbenzotriazole in EtOH-CH(OEt), gave the doubly chloro- bridged dimer [Cu,CI,(C,H,N,),] 1 and the novel alternating linear-chain polymer [{Cu,CI,(C,H,N,),},] 2 respectively, crystal structures of which have been determined; magnetic susceptibility studies show that complex 1 possesses intramolecular- and complex 2 intrachain- ferromagnetic coupling. Several groups have been exploring the co-ordination chemistry of benzotriazoles,' which is chiefly motivated by the anticorrosion properties of benzotriazole and substituted benzotriazoles towards certain metals, particularly copper and its alloys.'.' Moreover, 3d-metal benzotriazolate clusters encompass a range of interesting structural types 1 * 3 , 9 and frequently possess unusual magnetic and EPR proper- ties,4." 1 2 For CuCI, and 1 -methylbenzotriazole our studies show that a wide variety of different structures can be accessed through subtle changes in reaction conditions.Here we describe the identit1 of the products obtained from the CuC12-C,H,N3 reaction mixture in anhydrous EtOH in the absence of added counter ions. The complexes [Cu,C14(C,H,N3),] I and [{Cu,Cl,- (C,H,N3), ;,,I 2 were prepared? by the reaction of CuCI, and C,H,N, i n EtOH-CH(OEt), employing 1 : 2 and 1 : 1 mole ratios, respectively. Complex 2 was also isolated in pure form from thc solid-state endothermic reaction (1). Powders of 1- Compound I . t o a stirred green solution of CuCI, (0.1 3 g, 1 .O mmol) in EtOH ( 9 0 cm') was added CH(OEt), (3-4 cm3).This was refluxed for 30 min and added to a solution of C,H,N, (0.27 g, 2.0 mmol) in anhydrous I'tOH ( 1 5 cm'). The resulting blue-green solution was layered with hexanes Et,O ( I : 1) (50 cm3). Slow mixing yielded sky- blue crystals 01' I suitable for a crystal structure analysis. The crystals were collectcd by filtration, washed with Et,O and dried in air; yield c'2,H2xCI,( u 2 N , , requires C, 42.0; H, 3.50; CI, 17.7; Cu, 15.9: N, 2 1 .Oy(). Compound 2: CuCI, (0.25 g, 1.9 mmol) and C,H,N, (0.24 g, 1.8 mmol) wcrc dissolved in EtOH (SO cm') and CH(OEt), (5 cm'). The undisturbed grcen solution soon began to deposit well-formed, brown crystals of thc product. The flask was stored at ambient temperature for 2 ci, and the ci-yxtals (some were large enough for X-ray crystallography) were filtered oft'.washed with EtOH and Et,O, and dried in uacuo over PIO,,,; yield u i . 80% (Found: C, 31.4; H, 2.70; CI, 27.0; Cu, 24.3; N, 15.4. C,,H,,CI,CuZN, requires C. 31.4; H, 2.60; C1, 26.5; Cu, 23.7; N, c(/. 45::) ( F O U I I ~ : C. 42.1: H, 3.40; CI, 17.4: CU. 16.8; N, 20.8. 15.70'j,,)). empirical formulae CuC12(C7H 7N3)2 and CuCl,( C,H,N,) have been known since 1983 when Reedijk et a/. l 3 isolated them from the reactions of 1 -methylbenzotriazole with CuCI2*2H,O in ethanol-n-pentane. The authors pro- posed a halogen-bridged linear-chain structure with two monodentate ligands per Cu" for the I :2 complex, and suggested a bidentate bridging mode of C,H,N, in the 1 : 1 compound.The crystal structure of I (Fig. 1 ) consists of isolated dinuclear molecules with two bridging chloro ligands; a terminal chloride and two nitrogen atoms from two trans- C7H,N, ligands complete five-co-ordination at each metal. The bridging Cu,CI, unit is strictly planar, with a crystallographic inversion centre in the middle of the dimer. The geometry at each copper centre is square pyramidal with the basal plane comprising the two trans-nitrogen atoms and two trans- chloride ions; the apical site is occupied by the chloride ion which is basal to the other copper in the dimer. The in-plane Cu-Cl distances of 2.273(1) and 2.302(1) A are within the normal range, with the distance to the bridging chlorine slightly the longer, as expected. The Cu Cu' separation, the out-of- plane Cu-CI( 1 ') distance and the bridging Cu-CI( 1 )-Cu' angle in this complex are all towards the low end of the respective ranges observed for other, structurally similar tetragonal- pyramidal dichloro-bridged copper(r1) dimers.5 . l 6 The C7H,N3 groups in syn positions are nearly parallel, the angle between their mean planes being 4.3". There appear to be intradimer stacking interactions between these ligands on the two sides of the molecule [the shortest distance from the2318 J . CHEM. SOC. DALTON TRANS. 1995 CI( 1') - 1 " 1 C(20) Fig. 1 An ORTEP l 4 representation of complex 1. Most symmetry- related atoms are not labelled: Cu - - - Cu' 3.438( I), Cu-CI( 1) 2.302( I ) , 2.023( I ) , N(I)--N(2) 1.337(2), N(2)-N(3) 1.317(2) A; Cu-CI(I)-Cu' CU-CI( l'), 2.629( I ) , Cu-CI(2) 2.273( I), Cu-N(3) 2.019(2), Cu-N(I3) 88.l(l), Cl(l')-C~-Cl(l) 91.9(1), Cl(l')-C~-C1(2) 100.5(1), CI(I')-Cu-N(3) 94.3(1), Cl(l')-C~-N(l3) 93.2(1), Cl(1)- Cu-CI(2) 167.6(1), C1( I)-Cu-N(3) 89.0(1), CI(I)-Cu-N(13) 89.2(1), C1(2)-Cu-N(3) 90.1( I ) , CI(2)-Cu-N(13) 90.1( I), N(3)-Cu-N(13) l72.3( I)" N( I)N(2)N(3)C(S)C(4)C(5)C(6)C(7)C(9) mean plane is 3.50 8, for N(12')l.l $ Crystal data. C,,H,,CI,Cu,N,, 1, M = 801.51, monoclinic, space group P2,/n, c1 = 9.927(1), b = 15.627(1), c = 10.753(1) A, p = 96.69(1)", ti = 1656.71 A3, Z = 2, F(000) = 812, D, = 1.61 g cm ', T = 296 K, p = 15.71 cm-', 3938 reflections measured, 3600 unique, giving 3012 with F, > 6.00(F0) [Rin, = 0.0201],264 refined parameters, [A/oImax = 0.012, [ApImax, [Aplmi, = 0.299, -0.322 e A ', R ( = CJIF,I - \Fc\l/C\FO\) = 0.0242 (R' [ = [CM~\F,I .- ~ F c ~ ) 2 / X ~ ~ F o ~ z ] ~ ) = 0.0407) for 3012 independent observed reflections, ).t' = l / [ 0 2 ( F o ) + 0.0003F0z].C,,H,,CI,Cu,N, 2, M = 535.20, monoclinic, space group I2/m, (I = 8.877(1),h = 7.112(1),~ = 14.876(1)A,p = 93.94(l)",ti = 937.03 A'. Z = 2, F(OO0) = 532, D, = 1.90 g cm ', T = 296 K, p = 28.60 cm ', 1134 reflections measured, 1093 unique, giving 101 1 with F, > 4.00(F0)[Ri,, = 0.0141],97refinedparameters, [A/olmax = 0.045, [ApImax, [Aplmi,, = 0.342, -0.253 e A-', R = 0.0204, (R' = 0.021 5 ) for 101 1 independent observed reflections, unit weights. For both compounds unit-cell dimensions derived from a least- squares refinement of the setting angles of 25 automatically centred reflections ( 1 1 < 28 < 23") on a Nicolet P2, diffractometer upgraded by CRYSTAL LOGIC' ' with zirconium-filtered Mo-Ka radiation.Intensity data recorded using a 8-29 scan method to 28,,, = 54", with scan speed 4.5" min-' (1) and 3.0" min-' (2), and scan width 2.5" (1) and 2.7" (2) plus a1a2 separation. Lorentz, polarization and y-scan absorption corrections applied. Structures solved by direct methods using SHELX 86 and refined by full-matrix least-squares techniques (SHELX 76 "). Non-hydrogen atoms refined with anisotropic thermal parameters. All hydrogen atoms located by difference maps and their positions refined isotropically . Atomic coordinates, thermal parameters and bond lengths and angles have been deposited at the Cambridge Crystallographic Data Centre.See Instructions for Authors, J. Chem. Soc,., Dalton Trans., 1995, Issue I , pp. xxv-xxx. Fig. 2 An ORTEP representation of a part of complex 2. Symmetry- related carbon and nitrogen atoms are not labelled: Cu( 1 ) - . - Cu(2) N(I)-N(2) 1.335(3), N(2)-N(3) 1.313(3) A; Cu(2)-CI-Cu(l) 95.6(1), 3.556( I), CU( I)-CI 2.260( I ) , Cu(2)-CI 2.535( I), Cu(2)-N(3) I .986(2), CI-CU( I)-CI 90.4( I ) , CI-CU(~)-CI 78.5( I ) , CI-CU(~)-N(~) 89.4( I ) , N( 1)-N(2)-N(3) 108.0(2)" The crystal structure 1 of 2 (Fig. 2) is composed of linear, well-separated polymeric chains of Cu" atoms bridged asymmetrically by two chloro ligands. A regular alternation of two non-equivalent copper atoms [Cu( 1) and Cu(2)] occurs in the chain; Cu( 1 ) is surrounded by four chlorides in an almost perfect square-planar environment, whereas Cu(2) exhibits a trans-octahedral (p-CI),N2 environment.There is a mirror plane through Cu(2) and the C,H,N, ligands and a second one, parallel t o the first, through Cu(l), and a two-fold crystallo- graphic axis perpendicular t o the mirror planes through Cu( 1 ) and Cu(2); thus, each Cu" atom is located on a crystallogra hic noticeably shorter than the Cu(2)-CI bond length [2.535( 1) A], consistent with the lower co-ordination number for Cu( 1). The doubly-bridged chain with two alternating chomophores observed in 1 is unique for complexes of the formulation CuX,L (X = C1 or Br, L = monodentate ligand) as far as we are aware." Variable-temperature magnetic susceptibility data were collected for powdered samples of 1 and 2 in the temperature range 4.2 -294 K.For complex I, the effective magnetic moment, peff, per Cu" rises from 1.83 a t 294 t o 1.91 pB (pe 7. 9.274 x J T ') a t 4.2 K, which, together with the positive Weiss constant, is consistent with ferromagnetic coupling. Small anomalies for the xM-' = f ( T ) relation were observed in the lowest temperature range only. Hence, the experimental data between 4.2 and 20.0 K have been fitted t o the Bleaney- Bowers equation '' with a mole_cul_ar-field c_or<ec- tion 22,23 [spin Hamiltopianl.% =_-2J(S,*S,) + gPHS, S is the total spin operator S = S, + S,]. The best fitting param- eters obtained are 2J = + 7 cm-' and zJ' = - 1.1 cm-' ( J ' and z are the interdimer exchange parameter and the number of the nearest neighbouring dimers in the crystal lattice, respectively) by minimizing the function R [equation (2)] t o 4.46 x 10 '.centre of symmetry. The Cu( l)-Cl bond distance [2.260( 1 ) g: ] is For 2, the product x M 7 increases upon cooling, reaches a maximum (0.625 cm3 K mol ') a t ca. 2 1 K and then decreases to 0.563 cm3 K mol ' a t 4.3 K. Taking into account the crystal structure of this complex (see above), the magnetic data wereJ . WEM. sot.. DALTON TRANS. 1995 2319 fitted by the Heisenberg model of the magnetic interaction (Pade expansion series24 26 for S = i) assuming a first-order molecular-field correction to account for the interchain inter- actions. The best fitting parameters obtained are J = + 15.7 cm and A’ = -4.0 cm ’ with R = 2.05 x 10 ’.Hence, for z = 4 I,,,,,, = - 1 cm and Jlnter/.JInlra = 1’6. Consequently, complex 2 constitutes a very interesting example of a molecular ferromagnet in which one-dimensional chains are coupled an tiferromagnetically. The monodentate co-ordination of C,H,N,, observed even in the 1 . I complex 2 may in part account for the lack of long-term corrosion inhibition on copper by 1 -methyl- benzotr~amle.~’ Further detailed studies of 1 and 2 are in progress, and additional CuCI,-C,H,N, species--including high nuclarity clusters-arc under investigation. Acknowledgements This work was supported by the Greek General Secretariat of Research and Technology (Grant 91 ED 419 to S. P. P.) and John Bourari and Son Co. S. A. (to A. T.). References 1 J. Handley.D. Collison, C. D. Garner, M. Helliwell, R. Docherty, J . R. Lauson and P. A. Tasker, Angeiv. Chern., Int. Ed. Engl., 1993,32, 1036. 2 P. C. Andrews, W. Clegg. R. E. Mulvey, P. A. O’Neil and H. M. M . Wilson, J . Chem. Soc., Chem. Cornrnun., 1993, 1142. 3 B. G. Olby. S. D. Robinson, M. B. Hursthouse and R. L. Short, J . Chwn. Soc,., Dcilton Trans., 1990, 621 . 4 S. D. Moore and S. D. Robinson, Adv. Inorg. Chem., 1988,32, 171. 5 J. C . Pliikatouras, T. Bakas, C. J. Huffman, J. C. Huffman, V. Papacfthymiou and S. P. Perlepes, J. Chern. Soc., Dalton 7ians., 1994, 27.37. 6 E. Diamantopoulou, Th. F. Zafiropoulos, S. P. Perlepes, C . P. Raptopoulouand A. Terzis, Polyhedron, 1994,13,1593 and refs. therein. 7 S. L. F. A. da Costa and S. M. L. Agostinho, Corrosion (Houston), 1989,45,472.8 D. Sockalingum, M. Fleischmann and M. M. Musiani, Spectrochirn. Actrr, Part A , 1991,47, 1475 and refs. therein. 9 V. Tangoulis, E. Diamantopoulou, Th. F. Zafiropoulos, C. P. Raptopoulou, A. Terzis, E. G. Bakalbassis and S. P. Perlepes, J. Chern. Soc., Chem. Commun., in the press. 10 P. D. W. Boyd and R. L. Martin, J. Chern. So(.., Dtrlton Ti-(ins., 1981, 1069. 1 1 J. Baranowski, F. Padula, C. Goldstein, G. Kokoszka and A. R. Siedle, J. Phys. Chem., 1985,89, 1976. 12 A. Bencini, D. Gatteschi, J. Reedijk and C. Zanhini. Inorg. Chern., 1985,24, 207. 13 J. Reedijk, A. R. Siedle, R. A. Velapoldi and J. A. M. van Hest, Inorg. Chirn. Actrr, 1983, 74, 109. 14 C. K. Johnson, ORTEP, Report ORNL-5 138, Oak Ridge National Laboratory, Oak Ridge, TN, 1976.15 W. E. Hatfield. Comments Inorg. Chern., 1981, 1. 105. 16 W. E. Marsh, K. C. Patel, W. E. Hatfield and D. J . Hodgson, Inorg. Chem., 1983, 22, 51 1. 17 H. B. Bryn and C. E. Strouse, J. Am. Chem. Soc.. 1991, 113, 2501. 18 G. M. Sheldrick, SHELX 86, University of Gijttingen, 1986. 19 G. M. Sheldrick, SHELX 76, A program for crystal structure determination, University of Cambridge, 1976. 20 B. J. Hathaway, in Comprehensive Coordinntion Chemistry, eds. G. Wilkinson, R. D. Gillard and J. A. McCleverty, Pergamon, Oxford, 1987, vol. 5, ch. 53, pp. 640- 647. 21 B. Bleaney and K. D. Bowers, Proc. R. SOC. London, S r r . A , 1952, 214,451. 22 J. W. Stout and R. C. Chisholm, J. Chem. Ph~-.s., 1962,36, 979. 23 D. K. Towle, S. K. Hoffmann, W. E. Hatfield, P. Singh. P.Chaudhuri and K. Wieghardt, Inorg. Chern., 1985,24,4393. 24 T. Watanabe, J. Phys. SOC. Jpn., 1962, 17, 1856. 25 J. N. McElearney, S. Merchant and R. L. Carlin. Inorg. Chcrn., 1973, 26 G. A. Baker, jun., G. S. Rushbrooke and H. E. Gilbert, Phys. 27 J. B. Cotton and I. R. Scholes, Br. Corros. J.. 1967, 2, 1. 12, 906. Rev. A , 1964,135, 1272. Received 24th March 1995; Comuliuniuition 5,‘O 19 12EJ . C'HF_M. soc. DALTON TRANS. 1995 2317Copper( 11) C h lo ride4 - Methyl benzot riazole Chemistry:Variation of Product as a Function of Metal-to-LigandReaction Ratio; Synthesis, Structure and Properties of aDinuclear Complex and a Novel Chain Polymer with TwoAlter na t i ng C h ro mo p ho resKonstantina Skorda,a Evangelos G. Bakalbassis,*Sb Jerzy Mrozinski,c Spyros P.Perlepes,*naCatherine P. Raptopoulou and Aris Terzis * s da Department of Chemistry, University of Patras, 265 00 Patras, GreeceAristotle University of Thessaloniki, 540 06 Thessaloniki, GreeceLaboratory of Applied Quantum Chemistry, Department of General and Inorganic Chemistry,Institute of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 503 83 Wroclaw, PolandInstitute of Materials Science, NRCPS 'Demokritos: 753 70 Aghia Paraskevi Attikis, GreeceThe 1 : 2 and 1 : I reactions of CuCI, with 1 -methylbenzotriazole in EtOH-CH(OEt), gave the doublychloro- bridged dimer [Cu,CI,(C,H,N,),] 1 and the novel alternating linear-chain polymer[{Cu,CI,(C,H,N,),},] 2 respectively, crystal structures of which have been determined; magneticsusceptibility studies show that complex 1 possesses intramolecular- and complex 2 intrachain-ferromagnetic coupling.Several groups have been exploring the co-ordination chemistryof benzotriazoles,' which is chiefly motivated by theanticorrosion properties of benzotriazole and substitutedbenzotriazoles towards certain metals, particularly copper andits alloys.'.' Moreover, 3d-metal benzotriazolate clustersencompass a range of interesting structural types 1 * 3 , 9and frequently possess unusual magnetic and EPR proper-ties,4." 1 2 For CuCI, and 1 -methylbenzotriazole our studiesshow that a wide variety of different structures can be accessedthrough subtle changes in reaction conditions. Here we describethe identit1 of the products obtained from the CuC12-C,H,N3reaction mixture in anhydrous EtOH in the absence of addedcounter ions.The complexes [Cu,C14(C,H,N3),] I and [{Cu,Cl,-(C,H,N3), ;,,I 2 were prepared? by the reaction of CuCI, andC,H,N, i n EtOH-CH(OEt), employing 1 : 2 and 1 : 1 moleratios, respectively.Complex 2 was also isolated in pure formfrom thc solid-state endothermic reaction (1). Powders of1- Compound I . t o a stirred green solution of CuCI, (0.1 3 g, 1 .O mmol) inEtOH ( 9 0 cm') was added CH(OEt), (3-4 cm3). This was refluxed for30 min and added to a solution of C,H,N, (0.27 g, 2.0 mmol) inanhydrous I'tOH ( 1 5 cm'). The resulting blue-green solution waslayered with hexanes Et,O ( I : 1) (50 cm3). Slow mixing yielded sky-blue crystals 01' I suitable for a crystal structure analysis.The crystalswere collectcd by filtration, washed with Et,O and dried in air; yieldc'2,H2xCI,( u 2 N , , requires C, 42.0; H, 3.50; CI, 17.7; Cu, 15.9: N,2 1 .Oy(). Compound 2: CuCI, (0.25 g, 1.9 mmol) and C,H,N, (0.24 g,1.8 mmol) wcrc dissolved in EtOH (SO cm') and CH(OEt), (5 cm'). Theundisturbed grcen solution soon began to deposit well-formed, browncrystals of thc product. The flask was stored at ambient temperature for2 ci, and the ci-yxtals (some were large enough for X-ray crystallography)were filtered oft'. washed with EtOH and Et,O, and dried in uacuo overPIO,,,; yield u i . 80% (Found: C, 31.4; H, 2.70; CI, 27.0; Cu, 24.3; N,15.4. C,,H,,CI,CuZN, requires C. 31.4; H, 2.60; C1, 26.5; Cu, 23.7; N,c(/. 45::) ( F O U I I ~ : C.42.1: H, 3.40; CI, 17.4: CU. 16.8; N, 20.8.15.70'j,,)).empirical formulae CuC12(C7H 7N3)2 and CuCl,( C,H,N,)have been known since 1983 when Reedijk et a/. l 3isolated them from the reactions of 1 -methylbenzotriazolewith CuCI2*2H,O in ethanol-n-pentane. The authors pro-posed a halogen-bridged linear-chain structure with twomonodentate ligands per Cu" for the I :2 complex, andsuggested a bidentate bridging mode of C,H,N, in the 1 : 1compound.The crystal structure of I (Fig. 1 ) consists of isolateddinuclear molecules with two bridging chloro ligands; aterminal chloride and two nitrogen atoms from two trans-C7H,N, ligands complete five-co-ordination at each metal. Thebridging Cu,CI, unit is strictly planar, with a crystallographicinversion centre in the middle of the dimer.The geometry ateach copper centre is square pyramidal with the basal planecomprising the two trans-nitrogen atoms and two trans-chloride ions; the apical site is occupied by the chloride ionwhich is basal to the other copper in the dimer. The in-planeCu-Cl distances of 2.273(1) and 2.302(1) A are within thenormal range, with the distance to the bridging chlorine slightlythe longer, as expected. The Cu Cu' separation, the out-of-plane Cu-CI( 1 ') distance and the bridging Cu-CI( 1 )-Cu' anglein this complex are all towards the low end of the respectiveranges observed for other, structurally similar tetragonal-pyramidal dichloro-bridged copper(r1) dimers. 5 . l 6 TheC7H,N3 groups in syn positions are nearly parallel, the anglebetween their mean planes being 4.3".There appear to beintradimer stacking interactions between these ligands on thetwo sides of the molecule [the shortest distance from th2318 J . CHEM. SOC. DALTON TRANS. 1995CI( 1')- 1 " 1 C(20)Fig. 1 An ORTEP l 4 representation of complex 1. Most symmetry-related atoms are not labelled: Cu - - - Cu' 3.438( I), Cu-CI( 1) 2.302( I ) ,2.023( I ) , N(I)--N(2) 1.337(2), N(2)-N(3) 1.317(2) A; Cu-CI(I)-Cu'CU-CI( l'), 2.629( I ) , Cu-CI(2) 2.273( I), Cu-N(3) 2.019(2), Cu-N(I3)88.l(l), Cl(l')-C~-Cl(l) 91.9(1), Cl(l')-C~-C1(2) 100.5(1),CI(I')-Cu-N(3) 94.3(1), Cl(l')-C~-N(l3) 93.2(1), Cl(1)- Cu-CI(2)167.6(1), C1( I)-Cu-N(3) 89.0(1), CI(I)-Cu-N(13) 89.2(1),C1(2)-Cu-N(3) 90.1( I ) , CI(2)-Cu-N(13) 90.1( I), N(3)-Cu-N(13)l72.3( I)"N( I)N(2)N(3)C(S)C(4)C(5)C(6)C(7)C(9) mean plane is3.50 8, for N(12')l.l$ Crystal data.C,,H,,CI,Cu,N,, 1, M = 801.51, monoclinic, spacegroup P2,/n, c1 = 9.927(1), b = 15.627(1), c = 10.753(1) A, p =96.69(1)", ti = 1656.71 A3, Z = 2, F(000) = 812, D, = 1.61 g cm ',T = 296 K, p = 15.71 cm-', 3938 reflections measured, 3600 unique,giving 3012 with F, > 6.00(F0) [Rin, = 0.0201],264 refined parameters,[A/oImax = 0.012, [ApImax, [Aplmi, = 0.299, -0.322 e A ', R ( =CJIF,I - \Fc\l/C\FO\) = 0.0242 (R' [ = [CM~\F,I .- ~ F c ~ ) 2 / X ~ ~ F o ~ z ] ~ ) =0.0407) for 3012 independent observed reflections, ).t' = l / [ 0 2 ( F o ) +0.0003F0z].C,,H,,CI,Cu,N, 2, M = 535.20, monoclinic, space group I2/m,(I = 8.877(1),h = 7.112(1),~ = 14.876(1)A,p = 93.94(l)",ti = 937.03A'.Z = 2, F(OO0) = 532, D, = 1.90 g cm ', T = 296 K, p = 28.60cm ', 1134 reflections measured, 1093 unique, giving 101 1 withF, > 4.00(F0)[Ri,, = 0.0141],97refinedparameters, [A/olmax = 0.045,[ApImax, [Aplmi,, = 0.342, -0.253 e A-', R = 0.0204, (R' = 0.021 5 ) for101 1 independent observed reflections, unit weights.For both compounds unit-cell dimensions derived from a least-squares refinement of the setting angles of 25 automatically centredreflections ( 1 1 < 28 < 23") on a Nicolet P2, diffractometer upgradedby CRYSTAL LOGIC' ' with zirconium-filtered Mo-Ka radiation.Intensity data recorded using a 8-29 scan method to 28,,, = 54", withscan speed 4.5" min-' (1) and 3.0" min-' (2), and scan width 2.5" (1)and 2.7" (2) plus a1a2 separation.Lorentz, polarization and y-scanabsorption corrections applied. Structures solved by direct methodsusing SHELX 86 and refined by full-matrix least-squares techniques(SHELX 76 "). Non-hydrogen atoms refined with anisotropic thermalparameters. All hydrogen atoms located by difference maps and theirpositions refined isotropically . Atomic coordinates, thermal parametersand bond lengths and angles have been deposited at the CambridgeCrystallographic Data Centre. See Instructions for Authors, J. Chem.Soc,., Dalton Trans., 1995, Issue I , pp. xxv-xxx.Fig. 2 An ORTEP representation of a part of complex 2. Symmetry-related carbon and nitrogen atoms are not labelled: Cu( 1 ) - .- Cu(2)N(I)-N(2) 1.335(3), N(2)-N(3) 1.313(3) A; Cu(2)-CI-Cu(l) 95.6(1),3.556( I), CU( I)-CI 2.260( I ) , Cu(2)-CI 2.535( I), Cu(2)-N(3) I .986(2),CI-CU( I)-CI 90.4( I ) , CI-CU(~)-CI 78.5( I ) , CI-CU(~)-N(~) 89.4( I ) ,N( 1)-N(2)-N(3) 108.0(2)"The crystal structure 1 of 2 (Fig. 2) is composed of linear,well-separated polymeric chains of Cu" atoms bridgedasymmetrically by two chloro ligands. A regular alternation oftwo non-equivalent copper atoms [Cu( 1) and Cu(2)] occurs inthe chain; Cu( 1 ) is surrounded by four chlorides in an almostperfect square-planar environment, whereas Cu(2) exhibits atrans-octahedral (p-CI),N2 environment. There is a mirrorplane through Cu(2) and the C,H,N, ligands and a second one,parallel t o the first, through Cu(l), and a two-fold crystallo-graphic axis perpendicular t o the mirror planes through Cu( 1 )and Cu(2); thus, each Cu" atom is located on a crystallogra hicnoticeably shorter than the Cu(2)-CI bond length [2.535( 1) A],consistent with the lower co-ordination number for Cu( 1).Thedoubly-bridged chain with two alternating chomophoresobserved in 1 is unique for complexes of the formulationCuX,L (X = C1 or Br, L = monodentate ligand) as far as weare aware."Variable-temperature magnetic susceptibility data werecollected for powdered samples of 1 and 2 in the temperaturerange 4.2 -294 K. For complex I, the effective magnetic moment,peff, per Cu" rises from 1.83 a t 294 t o 1.91 pB (pe 7. 9.274 xJ T ') a t 4.2 K, which, together with the positive Weissconstant, is consistent with ferromagnetic coupling.Smallanomalies for the xM-' = f ( T ) relation were observed in thelowest temperature range only. Hence, the experimental databetween 4.2 and 20.0 K have been fitted t o the Bleaney-Bowers equation '' with a mole_cul_ar-field c_or<ec-tion 22,23 [spin Hamiltopianl.% =_-2J(S,*S,) + gPHS, S isthe total spin operator S = S, + S,]. The best fitting param-eters obtained are 2J = + 7 cm-' and zJ' = - 1.1 cm-' ( J ' and zare the interdimer exchange parameter and the number of thenearest neighbouring dimers in the crystal lattice, respectively)by minimizing the function R [equation (2)] t o 4.46 x 10 '.centre of symmetry. The Cu( l)-Cl bond distance [2.260( 1 ) g: ] isFor 2, the product x M 7 increases upon cooling, reaches amaximum (0.625 cm3 K mol ') a t ca.2 1 K and then decreases to0.563 cm3 K mol ' a t 4.3 K. Taking into account the crystalstructure of this complex (see above), the magnetic data werJ . WEM. sot.. DALTON TRANS. 1995 2319fitted by the Heisenberg model of the magnetic interaction (Padeexpansion series24 26 for S = i) assuming a first-ordermolecular-field correction to account for the interchain inter-actions. The best fitting parameters obtained are J = + 15.7cm and A’ = -4.0 cm ’ with R = 2.05 x 10 ’. Hence, forz = 4 I,,,,,, = - 1 cm and Jlnter/.JInlra = 1’6. Consequently,complex 2 constitutes a very interesting example of a molecularferromagnet in which one-dimensional chains are coupledan tiferromagnetically.The monodentate co-ordination of C,H,N,, observed evenin the 1 .I complex 2 may in part account for the lack oflong-term corrosion inhibition on copper by 1 -methyl-benzotr~amle.~’ Further detailed studies of 1 and 2 arein progress, and additional CuCI,-C,H,N, species--includinghigh nuclarity clusters-arc under investigation.AcknowledgementsThis work was supported by the Greek General Secretariat ofResearch and Technology (Grant 91 ED 419 to S. P. P.) andJohn Bourari and Son Co. S. A. (to A. T.).References1 J. Handley. D. Collison, C. D. Garner, M. Helliwell, R. Docherty,J . R. Lauson and P. A. Tasker, Angeiv. Chern., Int. Ed. Engl., 1993,32,1036.2 P. C. Andrews, W. Clegg. R. E. Mulvey, P.A. O’Neil andH. M. M . Wilson, J . Chem. Soc., Chem. Cornrnun., 1993, 1142.3 B. G. Olby. S. D. Robinson, M. B. Hursthouse and R. L. Short,J . Chwn. 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Wieghardt, Inorg. Chern., 1985,24,4393.24 T. Watanabe, J. Phys. SOC. Jpn., 1962, 17, 1856.25 J. N. McElearney, S. Merchant and R. L. Carlin. Inorg. Chcrn., 1973,26 G. A. Baker, jun., G. S. Rushbrooke and H. E. Gilbert, Phys.27 J. B. Cotton and I. R. Scholes, Br. Corros. J.. 1967, 2, 1.12, 906.Rev. A , 1964,135, 1272.Received 24th March 1995; Comuliuniuition 5,‘O 19 12
ISSN:1477-9226
DOI:10.1039/DT9950002317
出版商:RSC
年代:1995
数据来源: RSC